2-androsten-16-ol esters



United 3,232,964 Z-ANDRGSTEN-M-DL ESTERS Max N. Huffman, 3300 N.'Nev adaAve., Colorado Springs, Colo. No Drawing. Filed Feb. 142, 1964, Ser. No.344,197 4 Claims. (Ci. zen-397.5

wherein R represents hydrogen, a lower alkanoyl radical, a lowercarboxyalkanoyl radical or a lower alkanoxyalkanoyl radical. i

The compounds of the foregoing formula stimulate the reticuloendothelialsystem of mammals. For instance, at

a subcutaneous dose of 0.5 milligram per day forsix days in tli'e malemouse 2-androsten-16-ol significantly stimulates thereticuloendbtheli'al' system of the mouse without any toxic effects.Z-androsten-lG-ol as well as its hemisuccinafe produced noviriliz'ingeffect when givenorall'y at2'milligrams per day for fourteen days toyoung intact male rats, the size of the prostate, testes and levator aninotbeing different from the controls.

The reticuloendothelial system plays an important part incholesterolmetabolism. Cholesterol-containing macromolecular aggregates appear tobephagocytosed by cells of the reticuloendothelial system. Stimulationof the ret'iculoendothe'lial" system accelerates the reduction in bloodcholesterol levels. It has been observed that prernenopaus'al women arevirtually immune from coronary thrombosis, and these observationsled'lto the study ofthe effectof certain sex hormones in experimentaland clinical atherosclerosis. These studies indicate that certain sexhormonescause clinical improvement as well asa reversion toward normalofthe blood lipid picture in hypercholesterolemic individuals. On thebasis of such studies, it has been concludedthat hormonesmay have auseful role in therapy or prophylaxis of disorders associated'withabnormal levels of cholesterol in the hood, and that the efficacy ofthese substances may be due to their stimulating effect upon thereticuloendothelial system. A major limiting factor in the use ofhormones lies in their concomitanttsexual effect. Therefore, it isdesirable to produce'steroids having an effect upon thereticuloendothelial system without undesired sexual activity.

It is an object of this invention to provide steroids which have usefulphysiological properties. An additional object is to provide steroidswhich stimulate the reticulc endothelial system which have a negligiblevirilizing effect on mammals. It is another object of this invention toprovide efficient methods for producing such steroids. A further objectis to provide novel steroids of the series comprising 2-androsten-16-oland esters thereof which have useful physiological properties,particularly with respect to stimulation of the reticuloendothelialsystem. A further object is to provide efficient methods for producingsuch compounds from known starting materials. These tes Patent 3,232,964Patented Feb. 1, 1966 and other objects are apparent from and areachieved in accordance with the following disclosure.

In the compounds of thegeneral formula given above, R can representhydrogen or an ester group. The ester group can be a lower alkanoylradical such as acetyl, propionyl or butyryl. It can also be a lowercarboxyalkanoyl radical of the formula CO (CH ),,COOH wherein n is aninteger from 1 to 4, inclusive, suchas a hemi-succinyl. radical [-COCHCH COOH] R can. also represent a lower alkanoxyalkanoyl radical of thefor mula COAlkOCOR, wherein R is a lower alkyl. radical such as methyl,ethyl or propyl and Allc is an akylene radical or similar bivalentaliphatic radical containing 1 to 3 carbon atoms, inclusive. Thepreferred alkanoxyalkanoyl radical is the acetoxyacetyl radical butrelated r-adicals'are included in the compounds of this invention, suchas the propionoxypropionyl radical.

The compounds of this application are produced from Z-androsten-16-onewhich. can be synthesized according to the procedure of Fajkos and.Sorm, Chemicke Listy, vol. 4.7,pages 12071213 (1953). The keto group of2-androsten-lfi-one can be reduced by reaction with an. alkali metalhydride. of a metal of group 111A of the periodic table,.such.as sodium.borohydride, lithium aluminum hydride and potassium borohydride. Thisreaction ispreferably carried out ina lower alkanol. such as methanol,ethanolor similar aliphatic alcohol containing 1. to. 5 carbon: atoms.The reaction is usually conducted at room temperature, althoughtemperatures in the range of 0- C. can be used. After the reactionbetween the alkali metal hydride ofthe metal of the group IIIA and theketo group of 2-androsten-16-one has been completed it is advantageousto add a low molecular weight ketone such as acetone or methyl ethylketone to destroy the excess of reducing agent. Then, the2-androsten-l6B-ol is removed from thereaction mixture, preferably bydiluting the reaction mixture with water and refrigerating it. Thesteroid is insoluble in the dilute agueous solution and precipitates inthe form of an insoluble oil. 2-androsten-16B- 01 can be obtained fromthe insoluble oil by crystallization. Alternatively, 2-androsten-l6fi-olin oily. form can be converted into an ester such as the acetate byreaction with acetic anhydride or acetyl chloride in a tertiary aminesolvent such as pyridine, quinoline, dimethylaniline or the like. Thisreaction is ordinarily carried out at room temperature but can beconducted at temperatures in the range of 0 to 100C. The ester of2-androsten-16p-o1 can be isolated from the reaction mixture by dilutionwith water and refrigeration. The ester is insoluble in the diluteaqueous solution and separates out in crystalline form. It can bepurifiedby recrystallization from a lower alkanol such as methanol orethanol or from a lower aliphatic ketone such as acetone or methyl ethylketone. Purified 2-a'ndrosten-l6fl-ol can be obtained from thecrystalline ester of 2-androsten-16B-ol by hydrolysis with alcoholicalkali such as a solution of sodium hydroxide in aqueous alkanol such asmethanol or ethanol. This reaction is ordinarily carried out at refluxtemperature in the range of 50-150 C. After the reaction has beencompleted, the 2-androsten-16/3-ol can be isolated from the reactionmixture by dilution with water from which it separates as a crystallinematerial of high purity.

2-androsten-16ot-ol can be produced from Z-androsten- 16f3-ol byepimerization of its tosylate with sodium acetate in hot acetic acid,according to the general method described in Huffman Patent No.2,963,943, granted December 6, 1960. The resulting 2-androsten-l6a-olacetate can be hydrolyzedto 2-androsten-l6ot-ol with alcoholic alkaliand the latter can be converted to various esters such as the acetate,propionate, hemi-succinate. and the like as disclosed below.

Esters of 2-andr0sten-l6-ol can be produced by reaction of2-androsten-l6-ol with organic acid anhydrides or halides in thepresence of a tertiary amine solvent such as pyridine, quinoline ordimethylaniline. These reactions are generally carried out attemperatures in the range of 50150 C. over a period of time varying from/2 to hours. The ester of 2-androsten-l6-ol can be isolated from theresulting reaction mixture by dilution with water followed by heating toa temperature of at least 90 C. to hydrolyze the excess of organic acidanhydride or halide. Thereafter, the reaction mixture can be furtherdiluted with water and the insoluble steroid ester isolated therefrom byprecipitation with cooling or by extraction with an organic solvent suchas ether, chloroform, petroleum ether or the like. The esters can bepurified by recrystallization from lower alkanols such as methanol,ethanol and mixtures thereof with water as well as lower aliphaticketones such as acetone and methyl ethyl ketone as well as aqueousmixtures thereof.

The esters of 2-androsten-16-ol produced in accordance with thisinvention are usually crystalline white solids which are insoluble inwater but soluble in a variety of organic solvents. 2-androsten-l6-oland its esters can be administed orally to mammals or by injection. Whenadministered orally, they can be compounded in the form of tablets, orelixirs with inocuous pharmaceutical diluents or they can be in the formof capsules, with or without inocuous diluents. For parenteraladministration, they can be suspended in vegetable oil or in propyleneglycol.

The invention is disclosed in further detail by means of the followingexamples which illustrate various embodiments of the invention. It willbe understood by those skilled in the art that the procedures givenherein are illustrative only and are not intended to limit the inventionin scope. Various modifications in operating conditions and equivalentmaterials can be made without departing from the invention.

EXAMPLE 1 Z-zmdrosten-J 613-01 acetate C H: CH3

Five grams of 2-androsten-l6-one in 200 ml. of methanol was reduced with3 g. of sodium borohydride for 45 minutes at room temperature. Then 20ml. of acetone was added to destroy the excess of sodium borohydride andthe reaction mixture allowed to stand for 10 minutes. Finally 50 ml. ofwater was added and the mixture was distilled until turbidity appeared.The mixture was cooled to room temperature and refrigerated. The oilyprecipitate of 2-androsten-l6,B-ol solidified and was removed byfiltration, washed well with water and dried. It was dissolved in 50 ml.of pyridine and 50 ml. of acetic anhydride was added. The reactionmixture was kept at room temperature for 18 hours, then diluted with 1liter of cold water and refrigerated. After 2 hours the precipitate of2-androsten-l6fi-ol acetate was collected on a filter, washed well withwater and dried. After recrystallization from methanol it melted at 138C.; yield 4.2 g.

EXAMPLE 1A By a similar procedure to that of Example 1, but using 50 ml.of propionyl chloride in lieu of the acetic anhydride, there is produced2-androsten-16/3-ol propionate. In the same way 2-androsten-16fi-olbutyrate can be prepared, using 55 m1. of butyl chloride instead of theacetic anhydride.

a EXAMPLE 2 2-andr0sten-16fi-ol CH: C Ha EXAMPLE 3 2-androsten-16B-0lhydrogen succinate CH3 CH3 j Toooornorucoon A solution of 2.5 g. of2-androsten-l6B-ol and 3.8 g. of succinic anhydride in 50 ml. ofanhydrous pyridine was refluxed for 4 hours protected from moisture. Itwas then left at room temperature for 15 hours, diluted with 50 ml. ofwater and heated on a'steam bath for 30 minutes. Then ml. of water wasadded and the pH of the mixture adjusted to 3 with dilute sulfuric acid.The mixture was extracted with 800 ml. of ether, and the ether extractwas washed with water until neutral and then extracted with 500 ml. of0.1 N potassiumcarbonate solution. The potassium carbonate solutionwasthen acidified and extracted with 600 ml. of ether. The latterextract was washed with water until neutral and then dried withanhydrous sodium sulfate. The ether extract was filtered and evaporatedon asteam bath, leaving an oily residue of 2-androsten-l6fi-ol hydrogensuccinate. This was dissolved in 50 ml. of petroleum ether, evaporatedto 25 ml. volume, cooled to room temperature and chilled in a freezerfor 6 hours. The crystalline residue was removed by decantation and airdried. It was dissolved in 25 ml. of acetone, treated with activatedcarbon and filtered. The filter was washed with 25 ml. of acetone andthe combined acetone solutions were evaporated to about 25 ml. duringthe addition of six 50-ml. portions of petroleum ether. The resultingsolution was cooled to room temperature and chilled in a freezer for 4hours. The precipitate of 2-androsten-16 3-ol hydrogen succinate wasisolated by decantation and air dried; M.P. 79- 81 0; yield 2.6 g.

EXAMPLE 4 Z-androsten-I 6,8-01 acetoxyacetate EXAMPLE 2-andr0sten-16u-0lCH1; C H3 To a cooled solution of 2.3 g. of 2-androsten-16B-ol in 23 ml.of dry pyridine was added 3.2 g. of p-toluenesulfonyl chloride. After anhour in a cold bath the solution was allowed to stand at roomtemperature for 24 hours. It was then diluted with 460 ml. of ice watercontaining 3.2 g. of potassium bicarbonate and the precipi- Late ofZ-androstemlfi-ol p-toluenesulfonate was removed by filtration, washedwith water and dried in vacuo. It was dissolved in 150 ml. of glacialacetic acid containing 7.0 g. of fused sodium acetate and the solutionwas refluxed for one hour, then cooled and poured into 600 ml. of icewater containing sufiicient sodium hydroxide to neutralize the aceticacid. The mixture was extracted with one liter of n-butanol and thebutanol extract was washed with 1.0 N potassium hydroxide solution andwith water and evaporated to dryness.

The residues of 2-androsten-l6oL-ol acetate were dissolved in 750 ml. ofmethanol and 150 ml. of water containing 33 g. of potassium hydroxide.The solution was refluxed for one hour, then evaporated to about 500'ml. About 350 ml. of hot water was added and the solution evaporated ona steam bath until boiling ceased. The residue liquor was cooled to 25C. and extracted with one liter of butanol. The butanol solution waswashed with dilute potassium hydroxide solution, with 5% sodium chloridesolution and with water, then evaporated to dryness. The residue of2-androsten-l6w0l was recrystallized from petroleum ether (withactivated charcoal). It melted at 136-137 C.

EXAMPLE 6 2-andr0sten1-16a-ol acetate To a solution of 324 mg. of2-androste-n-l6a-ol in 5 ml. of dry pyridine was added 5 ml. of aceticanhydride. The resulting solution was left at room temperature for 24hours, then diluted with .200 ml. of ice water. The precipitate of2-:androsten-16 x-ol acetate was removed, washed with water and dried.On recrystallization from aqueous methanol it melted at 107.5 C.

I claim:

1. 2-androsten-16{3-ol hemi-ester of a dibasic acid of the formulaHOOC(CH COOH wherein n is an integer from 1 to 3, inclusive.

2. 2-androsten-l 6fi-ol hydrogen succinate.

3. 2-androsten-16fi-ol lower alkanoxy-lower-a1kanoate.

4. 2-androsten-16fl-ol acetoxyacetate.

References Cited by the Examiner UNITED STATES PATENTS 9/ 196-3 Bowerset al 260-3975 OTHER REFERENCES LEWIS GOTTS, Primary Examiner.

1. 2-ANDROSTEN-16B-OL HEMI-ESTER OF A DIBASIC ACID OF THE FORMULAHOOC(CH2)NCOOH WHEREIN N IS AN INTEGER FROM 1 TO 3, INCLUSIVE.